Common fish diseases

Here you'll find a guide to spotting five of the most common fish diseases, as well as tips on the best ways to treat them. The majority of common fish diseases are caused by poor water quality or an imbalance in water chemistry, so the best way to prevent your fish from becoming ill is to make sure that the water in your aquarium is correctly maintained. For more information on how to do this, head to our Maintaining a healthy aquarium section.

White Spot

As the name suggests, white spot is characterised by tiny white spots on the fish’s fins and body. Often caused by stress leading to an infection, these look like tiny distinct spots, and are in fact the reproductive stages of a tiny protozoan disease causing parasite. It is very contagious and needs to be treated straight away and for the full course of treatment or disease may come back. Chose a white spot treatment, there are many available.

Fin rot

As the name suggests, fin rot is a disease of the fin, and it can be recognised by the opaque or blood-streaked look of a fish's fin. Fin rot begins in the tip of the fin, and may spread to the base, at which point the fish will die. This disease only usually affects fish that are stressed or already have damaged fins due to excessive nipping from other fish. You can buy anti-bacterial medicine to treat fin rot from most pet stores.

Fungal Infections

Whilst the spores of fungus are always present in aquariums, they can become infectious if a fish already has damaged skin or gills. The main sign that your fish has a fungal infection is a white, cottony growth on their body. Anti-fungal medicines are usually the best option to fight the infection.

Cloudy Eye

As the name suggests, cloudy eye is a disease that involves a fish's eye turning cloudy, to the point that the fish loses vision. Whilst parasites in the aquarium are the most common cause of Cloudy Eye, severe stress, old age and malnutrition can all cause this condition. Cloudy Eye is generally cured through improving the water quality of an aquarium. Once the water quality is high enough, the fish will usually recover within 1-2 weeks.

Swim Bladder Disease

Swim Bladder Disease means a loss of buoyancy for your fish, so if you notice that they are staying at the bottom of the aquarium or only float at the surface, it's likely that they are suffering from this illness. There is considerable debate about the cause of this disease and the best way to cure it, so if your fish is suffering from this illness it's a good idea to speak to a vet or visit us at Pets at Home for advice.